1. Field of the Invention
The present invention relates to an indicating instrument for use in various devices or machines and particularly in an automobile.
2. Description of Related Art
In a conventional gauge installed in an automobile, generally an arc-shaped lighting tube is disposed behind a trans-illuminous dial plate along the indicating portion to illuminate the front surface thereof as shown in Japanese Unexamined Patent Publication Hei 2-80916.
Since the lighting tube is disposed along the indicating portion, the thickness of the above gauge can be made thin.
However, if a plurality of such gauges are installed in a car, the combined instrument structure becomes rather complicated and requires many parts, resulting in a cost increase in manufacturing.
In addition, different arc-shaped-lighting-tubes have to be provided for gauges having different-shaped dial plates.
Japanese Unexamined Patent Publication Hei 3-183912 discloses a dial gauge which has a partial-cylindrical reflector secured through a light diffusing plate to the back of the dial plate and a straight lighting tube disposed in the reflector. A driving shaft for a dial indicator extends from the back of the reflector through the reflector, the diffusing plate and the dial plate to the front of the dial plate.
However, the driving shaft for the dial indicator of the above described gauge is extremely long and the gauge becomes considerably thick. The extremely long shaft may increase the response time of the indicator and the hysteresis of the indication, thereby decreasing indication accuracy.